The present invention relates to a tool holder for machine tool and a tool driver used in the tool holder.
A tool holder as shown in FIG. 8, which is attached or detached on a spindle of a machine tool, has been already existed. The outline configuration of the tool holder is as follows.
That is, 1 is a tool holder main body, and consists of a direct cylindrical shaft part 1a, a flange part 1b and a taper-shank part 1c. A through-hole xe2x80x9caxe2x80x9d is formed in a rotating center part xe2x80x9cxxe2x80x9d of the tool holder 1, and female screw threads a1, a2 are formed in front and rear parts of the inner peripheral surface of the through-hole xe2x80x9caxe2x80x9d. Numeral 2 is a collet that is inserted into a taper hole of the direct cylindrical shaft part 1a. Numeral 3 is a collet fixing means that is fixed on a male screw thread xe2x80x9cbxe2x80x9d formed in the anterior outer peripheral surface of the direct cylindrical shaft part 1a, which consists of a nut body 3a, a ring rod member 3b and a combining member 3c. Numeral 4 is a pull-stud that is fixed on the posterior end of the taper-shank part 1c through the female screw thread a2.
Numeral 5 is an adjusting screw, which has a male screw thread formed in the outer peripheral surface and is installed on the middle of the length of the female screw thread a1 as the front and rear positions can be adjusted. A through-hole xe2x80x9ccxe2x80x9d is formed in the center of the adjusting screw 5, and the posterior part of a through-hole xe2x80x9ccxe2x80x9d is formed into hexagon hole c1. To the inside of a through-hole part a3 of a front side of the adjusting screw 5, a tool driver 6 shown in FIG. 9 is inserted closely and slidably in longitudinal direction.
An outer peripheral surface of the tool driver 6 is formed in smoothing surface, and driver pins 7, 7 protrude on the peripheral surface part of the tool driver 6 facing to its diameter direction. The driver pins 7, 7 are guided by guide rails xe2x80x9cdxe2x80x9d, xe2x80x9cdxe2x80x9d which are formed in an inner peripheral surface of the through-hole part 3a. Partial passage through-holes e1, e2, e3 which form a part of a below-mentioned passage through-hole formed in the rotating center part xe2x80x9cxxe2x80x9d of the holder main body 1 are provided to the center of the tool driver 6.
Numeral 8 is a cutting liquid communicating tube. A front end thereof is airtightly inserted into the partial passage through-hole e2 through an O ring, and on the other hand, a back end thereof is airtightly inserted into the anterior part of the central hole e4 of the pull-stud 4 through an O ring.
Numeral 10 is a cutter having a cutting fluid path e5 with a small diameter to the center of its main body. The cutter 10 is inserted into the through-hole part a3 of the holder main body 1 and a fitting female part forming the partial passage through-hole e3 in the forefront position of the tool driver 6 by way of the central hole xe2x80x9cfxe2x80x9d of the collet 2. As shown in FIG. 10, a peripheral surface notching part 10a called a tongue etc. is formed on a posterior part of the cutter 10. In this case, the fitting female part e3 is what a diameter part of a front end of the tool driver 6 is cut in the shape of a groove. A rubber packing 11 is pasted down a bottom surface of the fitting female part e3 with adhesives.
When equipping the holder main body 1 with the cutter 10 of the tool holder, first the nut body 3a of the collet fixing means 3 is loosened to make the collet 2 in the open status. Then, the bottom of the cutter 10 is inserted from the collet 2 front side by way of a central hole xe2x80x9cfxe2x80x9d of the collet 2, and the peripheral surface notching part 10a is fitted on the fitting female part e3. In this case, a back end surface of the peripheral surface notching part 10a is pressed to the rubber packing 11 at the bottom of the fitting female part e3. This status is held, and the nut 3a is clamped tight.
Therefore, the cutter 10 is fastened to the holder main body 1 through the collet 2, and the cutting fluid path e5 of the cutter 10 and the partial passage through-holes e1, e2, e3 of the tool driver 6 are communicated airtightly.
While using the tool holder, cutting fluid mist or cutting fluid supplied from a spindle side of the machine tool passes through the central hole e4 of the pull-stud 4, and thereafter reaches the passage through-hole xe2x80x9cexe2x80x9d of the holder main body comprising the cutting fluid communicating tube 8, the partial passage through-holes e1, e2, e3, and the through-hole part a3. Furthermore, it passes through the cutting liquid path e5 of the cutter 10, spouts from an opening of the tip thereof, and lubricates a friction part of the cutter 10 to a work.
There are the following troubles in the tool holder of the conventional machine tool.
That is, when equipping the holder main body 1 with the cutter 10, it is required to push backward the cutter 10 with sufficient force, to press the back end surface of the peripheral surface notching part 10a to the rubber packing 11 at the bottom of the fitting female part e3, and to clamp the collet fixing means 3 as holding this status. If thus attaching operation is not performed completely, the cutting fluid mist or the cutting fluid leaks from the part of the rubber packing 11 during a machining.
Besides, when the collet fixing means 3 fastens insufficiently the cutter 10 due to a certain cause, relative rotation of the cutter 10 to the holder main body 1 can not be regulated by any effect any longer, and processing by this cutter 10 can not continue.
Besides, when pressing the tool holder to the work strongly, the cutter 10 tends to slide backward to the collet 2. In this case, since the rubber packing 11 catches the back end of the cutter 10, the cutter 10 is not surely prevented from moving, and sometimes moves backward to the spindle. Accordingly, it is feared that machining accuracy may be injured.
An object of the present invention is to provide a tool holder for machine tool and a tool driver etc., which can solve the above-mentioned troubles.
The present invention relates to a tool holder for machine tool as follows. Plural guiding grooves parallel to a spindle direction are provided on the inner peripheral surface of a through-hole at a rotating center part of a tool holder main body. A tool drive that regulates relative rotation with the holder main body and can control front and rear positions by sliding along the spindle direction is assembled by the guiding grooves. A partial passage through-hole forming a part of the through-hole is formed at the rotating center part of the tool driver. A cutter comprises a cylindrical male surface part for sealing formed on the rear-outer peripheral part, a male surface part for regulating rotation comprising plane surface bodies formed at the front of it, and a half-moon shaped plane part formed at each front edge of them. Instead of the male surface part for regulating rotation and the half-moon shaped plane part, a groove for regulating longitudinal move comprising plane surfaces and half-shaped plane parts of the front and rear edges thereof may be formed. Here, the male surface part for regulating rotation is formed by cutting a fixed range of peripheral surface of the cutter, and the groove for regulating longitudinal move is formed by cutting a fixed range of the peripheral surface in concave shape. To the front-inner peripheral surface of the partial passage through-hole of the tool driver, a cylindrical female surface part for sealing to seal up the cylindrical male surface part for sealing of the cutter, and a fitting female part regulating relative rotation by fitting the plane surface bodies of the male surface part for regulating rotation or the concave of the groove for regulating longitudinal move. A barrier surface of the fitting female part contacts on the half-moon shaped plane part, thereby regulating relative rotation in longitudinal direction. A ring groove is formed to the inner peripheral surface of the cylindrical female surface part for sealing, and a ring-shaped packing for sealing an annular clearance between the cylindrical male surface part for sealing and the cylindrical female surface part for sealing is fitted into the ring groove.
According to this, the passage through-hole of the holder main body and the cutting fluid path of the cutter are airtightly communicated through the cylindrical male surface part for sealing, the cylindrical female surface part for sealing and the ring-shaped packing. This communicating status is not spoiled even if an amount of insertions changes within the comparatively large range. In this case, the tool driver is incorporated into the passage through-hole, by changing the front and rear positions of the tool driver, the length that the cutter protrudes from the front end of the holder main body can be changed arbitrarily.
The tool driver forms the partial passage through-hole comprising a part of the passage through-hole of the holder main body to the center thereof. To the anterior part of the partial passage through-hole are formed the cylindrical female surface part for sealing into which the cylindrical male surface part for sealing of the cutter is airtightly inserted through the O ring or its equivalent and the fitting female part which relative rotation is regulated by fitting the male surface part for regulating rotation, which a range of the peripheral surface is cut into the plane surface bodies or the groove part for regulating longitudinal move. On the other hand, to the posterior part of the partial passage through-hole is fitted the ring-shaped packing to insert the cutting fluid communicating tube airtightly. Besides, in the center of the outer peripheral surface part thereof is provided a driver pin which is engaged with the guiding groove engraved on the inner peripheral surface of the through-hole of the holder main body.